How does rDNS impact email deliverability when using dedicated IPs?

Reverse DNS (rDNS) is a critical component of email deliverability when using dedicated IPs. Technical documentation highlights that a matching PTR record for the sending IP address, aligned with the hostname in the HELO/EHLO greeting, is essential. A properly configured rDNS verifies the identity of the sending server, establishing trust with ISPs and improving sender reputation. Without a valid rDNS, emails are more likely to be flagged as spam or rejected. While client-specific rDNS is preferred for branding, some ESPs use their own, which is acceptable if forward and reverse DNS resolution works. A good domain reputation is crucial for rDNS, as a poor reputation can negatively impact deliverability. Experts agree that while rDNS is important, it's not a complete solution, and other factors play a significant role. Dynamic rDNS records may raise suspicion.

Reverse DNS (rDNS) plays a crucial role in email deliverability, particularly when using dedicated IPs. A properly configured rDNS record verifies the identity of the sending server, establishing trust with ISPs and improving sender reputation. Without a valid rDNS, emails are more likely to be flagged as spam or rejected by receiving mail servers. Dynamic rDNS records may raise suspicion, and a domain with a poor reputation used in the rDNS can negatively impact deliverability. Therefore, setting up rDNS is a best practice to ensure emails reach the intended recipients' inboxes.

Experts generally agree that while a correct rDNS record is important for email deliverability, it's not a guarantee of inbox placement. Not having a properly configured rDNS can definitely cause delivery problems. Some ESPs use their own rDNS even for dedicated IPs, which is generally fine as long as the IP resolves correctly to the domain name and back. Client-specific rDNS is often preferred for branding purposes, to remove any trace of the ESP, but it places responsibility on the client for maintaining the DNS records. A PTR record is a basic requirement for being considered legitimate by many receivers, especially when using dedicated IPs.

Technical documentation consistently emphasizes the necessity of correctly configured rDNS (PTR) records for email servers. A matching PTR record is required for the sending IP address, aligning with the hostname in the HELO/EHLO greeting. Without this match, emails are more likely to be flagged as spam or rejected. Reverse DNS lookups are a common anti-spam technique, verifying the sender's identity. Lack of a PTR record, or discrepancies between the PTR record and forward DNS, raise suspicion. rDNS guarantees email server authenticity, and its absence often leads to automatic categorization as spam. rDNS facilitates verification that the sender is who they claim to be, enhancing email legitimacy.